Low temperature sorbents for removal of sulfur compounds from fluid feed streams

ABSTRACT

A sorbent material is provided comprising a material reactive with sulfur, a binder unreactive with sulfur and an inert material, wherein the sorbent absorbs the sulfur at temperatures between 30 and 200° C. Sulfur absorption capacity as high as 22 weight percent has been observed with these materials.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to the removal of contaminants from gasstreams, and in particular this invention relates to the use of sorbentsfor removing sulfur from gas streams at low temperatures.

[0003] 2. Background of the Invention

[0004] Vapor-phase fuel streams are valuable commodities. Natural gasconsists of methane, carbon monoxide, hydrogen gas, and ethane.Liquified Petroleum Gases (LPG) are distillation products from bothnatural gas and oil-production processes, and are comprised of methane,ethane, propane, isobutane, butane and pentane. Other gases suitable forfuel gas use are derived from processes related to coal-gasification andoil shale-production. However, before such fuel streams are utilized,contaminants must be removed, particularly when advanced powergeneration systems are involved.

[0005] Sulfur-containing compounds (e.g. H₂S and CS₂) are the mosttypical contaminants in such fuel gas streams. Indeed, H₂Sconcentrations may range from 100 grains/100 cubic feet in blue andcarbureted water gas to several hundred grains per 100 cu. ft in coaland coke-oven gases. Refinery gases from sulfur crudes and natural gasesfrom sulfur-bearing regions may contain H₂S concentrations of severalthousand grains per 100 cu. ft.

[0006] Removal of sulfur is necessary for both environmental reasons andalso to protect the components (such as catalysts, fuel cells andturbines) of the power generation systems. Aside from power generationscenarios, certain chemical production processes also abhor sulfur infeed streams, for example, in natural gas-, ammonia-, oil-refining andpetrochemical refining-processes. For example, approximately 14 percentof U.S. natural gas reserves contain sulfur in the form of hydrogensulfide and at least 15 percent of the natural gas processed annuallyrequires treatment to remove hydrogen sulfide.

[0007] In addition to hydrogen sulfide, sulfur-containing compounds suchas mercaptans, organic sulfides, disulfides, thiophenes, thioesters,carbon oxysulfides, among others have to be removed from feed streams.

[0008] Some of the techniques for removing sulfur from feedstreamsincorporates high temperature processes. For example, U.S. Pat. No.4,089,809 assigned to the instant assignee, discloses a solid absorbentconsisting of iron oxide supported on silica for removal of hydrogensulfide from hot gaseous mixtures at temperatures between 538° C. (1000°F.) and 815° C. (1500° F.). A typical reaction process is as follows:

Fe₂O₃+3H₂S→2FeS_(1.5)+3H₂O  Equation 1

[0009] Aside from the high temperature requirements of this process, theefficacy of silicon oxide sorbents for the absorption of hydrogensulfide is further dictated by chemical equilibrium constraints, forexample when water vapor in the untreated gas (i.e., on the left side ofthe equation) is above a certain level.

[0010] Another relatively high temperature sorbent, this one containingzinc oxide, was disclosed in U.S. Pat. No. 4,088,736, issued to Courtyet al. This patent discloses a zinc oxide sorbent supported on silicaand/or alumina. The temperature range during the absorption step is 200°C. to 800° C., and more particularly between 300° C. and 650° C.

[0011] Zinc ferrite sorbents and a calcium-pretreatment process areutilized in a feed stream desulfurization procedure disclosed in U.S.Pat. No. 4,769,045 to Grindley. The zinc ferrite sorbent is prepared bymixing and calcining equimolar amounts of zinc oxide and iron oxide. Thetemperature range during the absorption step is about 538° C. to 649° C.At temperatures below 677° C., sulfur capture via calcium pretreatmentis very minimal.

[0012] Zinc titanate sorbents have been developed to resist degradationat the high temperature- and highly reducing coal gas-environmentsconcomitant with hot-gas environs. The use of zinc titanate sorbents ashigh temperature desulfurization sorbents is disclosed in U.S. Pat. Nos.4,313,820 and 4,725,415, both assigned to Phillips Petroleum Company.Absorption and olefin hydrogenation have a temperature range of about149° C. to 538° C. and hydrodesulfurization in the range of about 205°C. to 538° C.

[0013] U.S. Pat. No. 4,977,123 to Flytzani-Stephanopolous et al.,discloses a method of making mixed metal oxide sorbents suitable for usein fixed bed reactors. The mixed metal oxide absorbents are preparedusing calcined powders of a desired composition as starting materials,adding water to form a paste, extruding the paste, and drying andheating the extruded paste to yield the desired extrudate strength. Theoxides may be oxide mixtures of various metals such as for example,copper, iron, aluminum, zinc, titanium, and mixtures thereof. Inorganicbinder materials such as bentonite clay may also be added. The disclosedabsorption temperature is 650° C.

[0014] The instant applicant, in U.S. Pat. No. 5,866,503, discloses theuse of sorbent pellets for removing hydrogen sulfide in a coalgasification stream at temperatures at or above 260° C. (500° F.).Pellets are formed from a material reactive with hydrogen sulfide, abinder, and an inert material having a particle size substantiallylarger than the other components used to form the pellets. A diluent anda promoter may also be included during the formation process of thepellets.

[0015] Low temperature processes for removing sulfur from feed streamsexist. Generally, however, these systems are low sulfur capacityprocesses. Some methods use wet processes operated within a liquidphase, typically an amine solution. These methods have the disadvantageof producing secondary waste streams such as contaminated waste water.Corrosion-, and solution loss-problems also exist with amine-typeprocessing.

[0016] Activated carbon also is utilized in low-temperature sulfurremoval processes.

[0017] However, these systems have low capacities. And, the large carbonbeds required are mostly non-regenerable, leading to secondary wastestream problems.

[0018] The Stretford process is another low-temperature approach forremoving sulfur from feed streams. In the Stretford process, H₂S gas iscontacted with a scrubbing solution containing Vanadium in the +5valence state and anthraquinone disulfonic acid (ADA) in a sodiumcarbonate solution at pH 9. The H₂S is absorbed in an acid/base reactionand the resultant bi-sulfide ion is oxidized by the V⁺⁵ to produceelemental sulfur. V⁺⁵ is reduced to V⁺⁴ in this reaction but isregenerated using ADA and oxygen. The Stretford process forms harmfulsubstances and has very high capital costs.

[0019] In addition, the process has not consistently achieved its designperformance levels and has encountered many operating problems.

[0020] A need exists in the art for a solid sorbent to remove sulfurcompounds at low temperatures. The sorbent should exhibit high sulfurcapacity and be operable in the temperature range of betweenapproximately 30° C. and 200° C. Furthermore, the sorbent should berelatively inexpensive to manufacture and maintain.

SUMMARY OF THE INVENTION

[0021] It is an object of the present invention to provide a sorbent forsulfur scavenging below 200° C. which overcomes many of thedisadvantages of the prior art. Another object of the present inventionis to provide a sorbent that has an increased sulfur absorbing capacitybetween 30° C. and 200° C. A feature of the invention is the combinationof readily available sulfur-reactive materials with diluent and supportmaterials to produce a porous sulfur-absorbing substrate. An advantageof the present invention is that less materials are required in thereactor bed resulting in minimization of the reactor bed size andprolonged use of the bed. Another advantage is that the material isuseful in low-temperature production processes, thereby resulting inminimal costs.

[0022] Yet another object of the present invention is to provide asorbent suitable for both fixed/moving and fluidized bed reactorapplications. A feature of the invention is that the sorbents arecomprised of metal-containing oxide which is reactive with hydrogensulfide metal at the temperature range of 30 to 200° C. An advantage ofthe sorbent is that it has excellent efficiency, and it can extractvirtually all sulfur from the sulfur-containing feedstream so that nearzero ppm levels of hydrogen sulfide concentrations in the feedstream areachieved.

[0023] Briefly, the invention provides material for absorbing sulfur,the material comprising a compound reactive with sulfur; an inertsubstance combined with the compound to create a mixture; and a binderto shape the mixture.

[0024] Also provided is a material for absorbing sulfur, the materialcomprising copper hydroxide; an inert material present at a weightpercent of the material of approximately 7 to 12 percent; a bindermaterial present at approximately 8 to 12 weight percent of thematerial; and a diluent material present at approximately 15 to 25weight percent of the material.

[0025] Specifically, the invention provides a sorbent which ischemically and physically stable for use in sulfur removal processes attemperatures between 30° C. and 200° C., the sorbent comprising amaterial reactive with hydrogen sulfide, a binder unreactive withhydrogen sulfide, and an inert diluent or a support, wherein saidmaterial reactive with hydrogen sulfide is unreactive with all othercomponents of said mixture.

BRIEF DESCRIPTION OF THE DRAWING

[0026] The invention together with the above and other objects andadvantages will best be understood from the following detaileddescription of the preferred embodiment of the invention shown in theaccompanying drawing, wherein:

[0027]FIG. 1 is a graph showing sulfur uptake of exemplary sorbents, inaccordance with features of the present invention; and

[0028]FIG. 2 is a graph showing exit sulfur concentrations of sulfur instreams treated with the invented sorbent, in accordance with featuresof the present invention.

DETAILED DESCRIPTION

[0029] The present invention discloses compounds exhibiting high sulfurabsorbing capacity for temperatures in the range of 30° C. to 200° C.The invented materials have shown very high sulfur capacity (15-20weight percent) when contacted with sulfur-containing streams havingsulfur ppm concentrations as high as 1.2 percent (12,000 parts permillion). Specifically, the invented sorbents are capable of adsorbingsulfur compounds from a gaseous feed of about 5 to 22 weight percentbased on the weight of the sorbent in the above-stated temperaturerange.

[0030] The materials incorporated in the invented mixture are readilyavailable and the method for preparing the pellets is very simple,therefore leading to cost-effective production. Also, the materialsincorporated into the sorbent mixture are not hazardous and will notcause disposal problems. Since the sulfur capacity of the sorbent isvery high, the amount of sorbent required in desulfurization processesis low; therefore the size of the reactor bed can be minimized. As notedsupra, the invented sorbents can be utilized in fluidized/transport bedreactors or fixed bed reactors.

[0031] The invented sorbent can be utilized in a myriad of forms. Forthe sake of simplicity, pellets were formed from the invented sorbentand utilized to provide the data contained herein.

[0032] Chemically- and physically-stable sorbent pellets were utilizedin sulfur removal processes in the temperature range of 30° C. to 200°C. Generally, the mixture comprises a material reactive with hydrogensulfide, a diluent/support, and a binder unreactive with hydrogensulfide.

[0033] Component ranges of the invented sorbent are as follows: Reactivematerial: 30 to 70 percent by weight; Inert diluent: 20 to 60 percent byweight; and Binder:  2 to 45 percent by weight.

[0034] When sorbents are prepared utilizing impregnation of inertsupports, reactive material concentration may vary from 5 to 60 wt %.

[0035] Preparation Detail

[0036] The sorbent material is being prepared by blending the reactivematerial (an exemplary material being copper hydroxide) with inertmaterials such as calcium sulfate or titanium dioxide, and a binder suchas bentonite. The said mixture is mixed with water to produce a slurryand then either extruded or extruded/marumerized to make pellets withthe desired shape. These materials can be spray dried or granulated toprepare sorbents suitable for fluidized bed/transport reactorapplications. The sorbent pellets should be calcined to be converted toa usable form. The sorbents can also be prepared by impregnating inertmaterials with the said reactive materials.

[0037] Other sorbent preparation methods, well known in the art, can beutilized in the preparation of sorbents with the reactive materialsdescribed in the patent.

[0038] Pellets made up of the above components may be prepared bysolid-state mixing and adding a sufficient amount of water to cause thepellets to agglomerate or adhere together. Mixer-pelletizer orcompressing equipment and other methods of agglomeration known in theprior art may be used for this purpose. The agglomerated pellets aredried and calcined at an elevated temperature to convert them to durableform. Drying the pellets occurs in an oven at a temperature over 100° C.(212° F.) and preferably about 100° C. for approximately 7-10 hours. Thedried pellets are then calcined at a temperature between 50° C. and 150°C. for less than nine (9) hours. At this calcination temperature andduration, the material reactive with hydrogen sulfide is unreactive withall other components of the mixture.

[0039] The resulting pellets exhibit increased sulfur absorbing capacityin the temperature range of 30° C. to 200° C. compared to currentlyavailable commercial blends. The crush strength of the fresh pellets arein the range 3-4 lb per pellet and increases to 4-5 lb per pellet aftersulfidation.

[0040] Hydrogen Sulfide—Reactive Material Detail

[0041] Reactive materials can be inorganic materials selected from thegroup consisting of copper hydroxide, copper (II) oxide, iron (III)hydroxide, potassium bicarbonate, rubidium hydroxide, zinc oxide, zincoxide hydrate, lithium hydroxide, sodium peroxide, and mixtures thereof.Copper hydroxide is preferred for use over its effective temperaturerange of about 50° C. to 200° C. For operation between 30° C. and 50°C., rubidium hydroxide or lithium hydroxide may be employed. It shouldbe noted that the reactive metal salts of the compounds, such as theacetates, formates, carbonates and nitrates can be used instead of theoxides inasmuch as the oxides can be derived from the salts.

[0042] Generally, the reactive compound will contain a metal selectedfrom the group consisting of copper, iron, potassium, rubidium, zinc,lithium, sodium, or combinations thereof. The reactive material reactswith the sulfur via the following reaction mechanism:

MO+H₂S→MS+H₂O  Equation 2

[0043] wherein MO is a metal oxide, and MS is the salt formed with thesulfur.

[0044] Inert Material Detail

[0045] Inert material utilized in the invented composition can behomogenous in structure, or comprise a plurality of various grain sizes.In a preferred composition, the inert material is comprised of a firstdiluent portion and a second portion.

[0046] The first inert portion (i.e. diluent) provides stability to thecomposition inasmuch as it does not enter into the reaction withhydrogen sulfide or otherwise alter during the reaction period. Thediluent inert material may be selected from a group consisting oftitanium oxide, titanium dioxide, calcium sulfate, calcium phosphate,calcium silicate, magnesium sulfate, zinc silicate, zinc aluminate, andalumino silicates. It is used at a concentration of 0 to 40 weightpercent of the pellets and preferably 10 to 30 percent. In preparingpellets containing the diluent inert material, temperatures high enoughto cause a reaction between this material and the reactive oxide are tobe avoided to prevent loss of reactivity. Calcium sulfate and titaniaare preferred material for this component.

[0047] The second portion of the inert material contains large particlesso as to obtain necessary porosity in the pellets. This compares withthe reactive component portion of the sorbent which have relativelysmaller particle sizes for maximum reactivity, strength, and optimumformation of voids around the larger inert particles.

[0048] Particle sizes of the second portion of the inert material may bevaried, depending on the desired pellet sizes for different types ofreactor systems. For fixed/moving bed reactors, spherical or cylindricalpellets over 1 millimeter (mm) in size, and typically 2 to 5 mm, areused. For pellets of this size, particle sizes of the second portion ofthe inert component with large particle size may be over 50 microns andpreferably 75 to 700 microns (25 to 200 mesh). Fluidized bed/transportreactors employ pellets under 500 microns, and the second portion of theinert component with large particle size for this pellet size could besized under 150 microns, preferably 0.5 to 5 microns.

[0049] The second portion inert material containing larger particles foruse in the pellets may be selected from the group consisting of silicagel, silica, alumina, alumina gel, titania gel, calcium sulfate, zincsilicate, zinc aluminate, and sand. Silica gel or calcium sulfate arepreferred.

[0050] As noted supra, the second portion of the inert material mayincorporate material with varying particle sizes, but at least two (2)weight percent of the particles should be made up of particlesapproximately twice as large as the reactive material. Preferablybetween 2 and 30 weight percent of the total inert material (i.e., thefirst and second portions combined) should be comprised of particlestwice as large as the reactive material. Up to 40 percent of the secondportion of the inert material could be particles twice in size comparedto the size of the particles comprising the reactive compound.

[0051] The inert material may be provided in the pellets at a totalconcentration of 0 to 20 weight percent and more preferably at 2 to 10weight percent. Other components of the pellets become loosely packedaround the larger particles of this inert material, creating betterporosity in the pellets. Upon being subjected to exposure at highertemperatures in preparation or operation, the large particle size inertmaterial undergoes a decrease in surface area, but porosity of thepellets is increased due to creation of additional voids around thelarge particles.

[0052] Binder Detail

[0053] A binder is required in the pellets to keep them together. Thebinder may comprise inorganic or organic materials or a mixture thereof.For example, suitable inorganic materials include, but are not limitedto, kaolinite, other alumino silicates, calcium sulfate, cement, ormixtures of these materials.

[0054] Organic binders that can be used include substances selected fromthe group consisting of hydroxypropyl methyl cellulose, molasses,starch, polyvinyl acetate, cellulose, hydropropyl cellulose, ligninsulfonate, and mixtures thereof.

[0055] Concentration of the binder in the pellets may range from 2 to 60weight percent.

[0056] It is noted that calcium sulfate is included within the listingof materials for both the first and second inert materials as well asfor the binder.

[0057] The binder facilitates shaping the sorbent material into adesired shape, such as pellets, spheres, rods, or other configuration tomaximize sorbent contact with the sulfur laden fluid to be treated.

[0058] The invention is illustrated by the following examples.

[0059] TGA Data with Powdered Reactive Materials

[0060] Extent of sulfur uptake by the powder was determined using a TAInstruments 951 Thermogravimetric Analyzer (TGA-2050 TA Instruments).Approximately 25-50 mg of sample was utilized for each test.Sulfur-containing gases were introduced at 90 cc.min at the desiredsample temperature. Tests were conducted with sulfur gases in thepresence of both reducing gases and non-reducing gases. The compositionof the sulfur containing reducing gas mixture was 0.4% H₂S, 51.9% H₂,22% CO₂, 1.67% CH₄ and 24% N₂, while the composition of thesulfur-containing non-reducing gas mixture was 1.28% H₂S in nitrogen orargon.

[0061] In the TGA experiments, weight gains of the pellet is measuredafter introduction of the gas. The amount of sulfur uptake by a solidmaterial is usually calculated utilizing the weight gain. A typical TGAcurve for copper (II) oxide is depicted in FIG. 1. When secondaryreactions do not occur during sulfur sorption, the weight gain in TGA isdirectly proportional to the sulfur uptake. However, when secondaryreactions take place, the weight gain is not directly related to theweight gain and the solid is analyzed using a sulfur analyzer todetermine the actual sulfur uptake after the TGA experiments. Theanalyzer is the SC-432DR™ model manufactured by LECO Corp. of St.Joseph, Mich.

[0062] Sulfur uptake values (after exposure to H₂S in reducing gas)determined by the TGA/LECO experiments are listed in Tables 1 and 2,below, for reducing and non-reducing gas, respectively.

[0063] Compared to commercially-available materials, many of theinvented sorbents showed exceptional sulfur uptake, 16-22 weightpercent, in the temperature range of 50 ° C. to 200° C. Both rubidiumand lithium hydroxide showed reasonable sulfur capacity, even at 30° C.These results are superior to those obtained from commercial sorbents,such as molecular sieves, carbon-containing industrial sorbents, and thecommercial solvent methyl diethyl amine (MDEA). As such, all ten of theinvented sorbents provide superior sulfur absorption compared tocommercially-available compositions. The LECO/TGA sulfur uptake valuesafter exposure to H₂S in non-reducing gases (Argon or nitrogen) arelisted in Table 2. TABLE 1 Sulfur Loading Values Obtained from TGA/LECOAnalysis with H₂S in Reducing Gas Sulfur Uptake (Weight Percent)Compound 200° C. 150° C. 100° C. 50° C. 30° C. Copper Hydroxide 19.322.0 19.1 16.8 5.6 Copper II Oxide 17.6 12.1 3.3 0.3 0.2 Iron IIIHydroxide 17.6 3.8 2.2 1.7 1.4 Potassium Bicarbonate 19.9 6.4 0.01 0.01<0.01 Rubidium Hydroxide 6.1 4.7 6.6 5.1 7.5 Zinc Oxide 7.7 5.6 4.1 2.82.6 Zinc Oxide Hydrate 5.5 2.9 1.6 1.2 0.9 Lithium Hydroxide 3.7 0.3 0.58.4 6.9 Sodium Peroxide 4.9 6.2 9.2 3.3 4.2 Ferric Oxide 4.3 1.5 1.2 1.00.2 COMMERCIALLY- AVAILABLE SORBENTS: Activated Carbon 3.04% and 2.79%at 30° C. MDEA solvent 0.001-2.17 moles/mole (or 2.85 × 10⁻⁴ to 0.62 wt%) at 40-65° C. Molecular Sieve 5A 0.03-0.21 weight percent at 30-200°C.

[0064] The inventors found that most of the sorbents had a higher sulfurcapacity in the presence of reducing gas but rubidium hydroxide seems toperform better in the presence of non-reducing gas. The powderedmaterials also were tested with 1 percent carbonyl sulfide in nitrogenat both 50 and 150° C. Copper hydroxide had a sulfur uptake of 5.5weight percent and lithium hydroxide had a sulfur uptake of 1.7 weightpercent at 150° C. but showed a lower sulfur uptake at 50° C. (copperhydroxide—0.9 wt % and lithium hydroxide at <0.01 wt %). This indicatesthat these two compounds are suitable for absorption of carbonyl sulfideat 150° C. TABLE 2 Measured Sulfur-Uptake Values After Exposure to H₂Sin Non-Reducing Gas. Total Sulfur Uptake (Weight %) Compound 200° C.150° C. 100° C. 50° C. 30° C. Copper Hydroxide 16.8 15.4 14.6 10.3 5.1Rubidium Hydroxide 13.4 13.6 —  5.0 Iron Hydroxide 8.4 —  1.8 — — CopperHydroxide 8.7  8.3 — — —

[0065] When these materials were tested with tetrahydro thiophene (180ppm) in nitrogen at both 50° C. and 150° C., the sulfur uptake valueswere very low with lithium hydroxide showing the highest absorption of0.85 wt % at 50° C. Lithium hydroxide also had a sulfur uptake of 0.67wt % and 0.79 wt % at 50° C. and 150° C. respectively when it wasexposed to dimethyl sulfide (1500 ppm) in nitrogen. Copper hydroxide hada sulfur uptake of 0.22 and 0.60 wt % at 50° C. and 150° C. respectivelywhen it was exposed to dimethyl sulfide.

[0066] Test Results with Pelletized Sorbent

[0067] A pelletized sorbent structure was constructed with the followinggeneral formulation: copper hydroxide present at between 60 and 65weight percent; an inert material present at a weight percent of thematerial of approximately 7 to 12 percent; a binder material present atapproximately 8 to 12 weight percent of the material; and a diluentmaterial present at approximately 15 to 25 weight percent of thematerial.

[0068] Specific sorbent pellets were prepared using the followingcomposition: Copper Hydroxide  550 grams Silica Gel 37.5 grams (35-60mesh) Silica Gel 37.5 grams (100-200 mesh) Bentonite   90 grams Titaniumdioxide  170 grams

[0069] The powders were mixed with a sufficient amount of water,extruded and marumerized (spherical) to obtain pellets having an averagediameter of 3 mm. The pellets were calcined at 100° C. for eight hours.

[0070] These sorbent pellets were tested in the TGA at 150° C. withhydrogen sulfide in reducing gas. The measured (LECO) sulfur uptake ofthe solid was 15 weight percent. These results indicate that the sulfurcapacity for the sorbent pellets was superior to typical sorbents.Typical sorbents have sulfur capacity less than 3 weight percent, asshown in Table 1.

[0071] The sorbent pellets were also tested in an atmospheric fixed bedbench scale reactor. The reactor bed had a 6 inch bed height and 2 inchdiameter. The inlet hydrogen sulfide concentration was 2000 ppm innitrogen. The gas was introduced to the reactor at a space velocity of1000 hr⁻¹. The temperature of the reactor bed was maintained at 150° C.The outlet hydrogen sulfide concentration measured as a function of timeis shown in FIG. 2. The outlet hydrogen sulfide concentration was nearzero ppm during the first 40 hours of testing. At approximately 45 hoursafter testing began, sulfide concentration of the outlet gas begins toincrease, thereby indicating saturation of the sorbent. This indicatesthat the sorbent has a very high efficiency and is capable of reducingthe sulfur level from 2000 ppm to near zero ppm.

[0072] While the invention has been described with reference to detailsof the illustrated embodiment, these details are not intended to limitthe scope of the invention as defined in the appended claims. Forexample, the sorbent can comprise a compound reactive to sulfur, whereinthe compound is impregnated onto, into or otherwise reversibly adheredto inert porous substrates to form reactant sorbents. These poroussubstrates can be large granular materials selected from the groupconsisting of titania, silica, alumina, alumino silicate, zirconia,zeolites, carbon, or combinations thereof. These porous substrates canrange in size from 100 microns to 3-4 millimeters.

The embodiment of the invention in which an exclusive property orprivilege is claimed is defined as follows:
 1. A material for absorbingsulfur at between 30° C. and 200° C., the material comprising: a) acompound reactive with sulfur; and b) an inert substance combined withthe compound.
 2. The material as recited in claim 1 wherein the inertsubstance is a porous substance which is impregnated with the compound.3. The material as recited in claim 2 wherein the inert substance isapproximately 100 microns to 4 millimeters in size.
 4. The material asrecited in claim 1 wherein the compound and the inert substance is mixedwith a binder.
 5. The material as recited in claim 2 wherein the inertsubstance is a porous substance selected from the group consisting oftitania, silica, alumina, alumino silicate, zirconia, zeolites, carbonor a combination thereof.
 6. The material as recited in claim 1 whereinthe compound is rubidium hydroxide and the absorption occurs at 30° C.7. The material as recited in claim 1 wherein the compound is copperhydroxide and the absorption occurs at between 30° C. and 200° C.
 8. Thematerial as recited in claim 1 wherein the material contains from 2 to80 weight percent of the inert substance.
 9. The material as recited inclaim 1 wherein the inert substance is comprised of a first portion anda second portion.
 10. The material as recited in claim 9 wherein thefirst portion is a diluent selected from the group consisting oftitanium oxide, calcium sulfate, calcium phosphate, calcium silicate,magnesium sulfate, zinc silicate, zinc aluminate, and alumino silicate.11. The material as recited in claim 9 wherein the second portion of theinert substance comprises up to 40 weight percent of the material andthe second portion has particle sizes larger than particle sizes of thecompound.
 12. The material as recited in claim 9 wherein at least twoweight percent of the second portion has particles that are twice aslarge as particles comprising the compound.
 13. The material as recitedin claim 8 wherein the first portion is a diluent and whereinapproximately 2 to 30 weight percent of the second portion has particlesthat are twice as large as particles comprising the compound.
 14. Thematerial as recited in claim 9 wherein the second portion is a granularsubstrate selected from the group consisting of silica gel, silica,alumina, alumina gel, titania gel, calcium sulfate, zinc silicate, zincaluminate, sand or combinations thereof.
 15. The material as recited inclaim 1 wherein the material contains from 30 to 70 weight percent ofthe compound.
 16. The material as recited in claim 4 wherein the binderis an organic compound selected from the group consisting ofhydroxypropyl methyl cellulose, molasses, starch, polyvinyl acetate,cellulose, hydropropyl cellulose, lignin sulfonate, or combinationsthereof.
 17. The material as recited in claim 4 wherein the binder is aninorganic compound selected from the group consisting of bentonite,kaolinite, alumino silicates, calcium sulfate, cement, or mixturesthereof.
 18. A material for absorbing sulfur, the material comprising:a) copper hydroxide; b) an inert material present at a weight percent ofthe material of approximately 7 to 12 percent; c) a binder materialpresent at approximately 8 to 12 weight percent of the material; and d)a diluent material present at approximately 15 to 25 weight percent ofthe material.
 19. The material as recited in claim 18 wherein the inertmaterial is silica gel and half of the silica gel is present asparticles at 35-60 mesh while the other half of the silica gel ispresent as particles at 100-200 mesh.
 20. The material as recited inclaim 18 wherein the binder is bentonite.
 21. The material as recited inclaim 18 wherein the diluent is titanium dioxide.
 22. A method forproducing a sorbent capable of removing sulfur from a gas stream attemperatures ranging from 30° C. to 200° C., the method comprising: a)combining a sulfur reactive compound with an inert material and a binderto create a homogenous mixture; b) pelletizing the mixture; and c)calcining the pelletized mixture at a temperature sufficient to solidifythe mixture.
 23. The method as recited in claim 22 wherein the sulfurreactive compound is an oxygen containing compound selected from thegroup consisting of copper hydroxide, copper (II) oxide, iron (III)hydroxide, potassium bicarbonate, rubidium hydroxide, zinc oxide, zincoxide hydrate, lithium hydroxide, sodium peroxide, and ferric oxide. 24.The method as recited in claim 22 wherein the inert material is agranular substrate selected from the group consisting of silica gel,silica, alumina, alumina gel, titania gel, calcium sulfate, zincsilicate, zinc aluminate, sand or combinations thereof.
 25. The methodas recited in claim 22 wherein approximately 2 to 30 weight percent ofthe inert material has particles twice as large as particles comprisingthe compound.
 26. The method as recited in claim 22 wherein the compoundcomprises between 30 to 70 weight percent of the sorbent.